Defrost the salmon. Remove outer savoy cabbage leaves and cut out the stalk in a wedge shape. Loosen some leaves, cut the stalk a little flatter and blanch for about 2 minutes. Sprinkle the salmon with lemon juice and salt it a bit. Wrap blanched leaves around the salmon. Cut the remaining savoy cabbage into small pieces.
Clean, clean and slice the mushrooms. Peel and finely chop the onion. Wash, quarter and seed the tomatoes. Cut the flesh into small cubes. Melt 1 tablespoon of fat. Fry onion and mushrooms in it. Season with salt and pepper. Deglaze with 200 ml water and cream, bring to the boil and add sauce thickener. Fry the savoy cabbage in hot oil while turning for about 5 minutes. Also season with salt and pepper. Add mushroom cream and diced tomatoes, simmer for another 5 minutes. Meanwhile, fry the salmon in the remaining hot fat, turning over, for about 5 minutes.
Season with salt and pepper. Deglaze with 200 ml water and cream, bring to the boil and add sauce thickener. Fry the savoy cabbage in hot oil while turning for about 5 minutes. Also season with salt and pepper. Add mushroom cream and diced tomatoes, simmer for another 5 minutes. Meanwhile, fry the salmon in the remaining hot fat, turning over, for about 5 minutes. Arrange salmon and vegetables in cream portions. Serve garnished with lemon